Pimples on Your Chin, Jawline, or Neck

The culprit: Your period. Hormones like testosterone fluctuate throughout your cycle and make your glands produce more oil, which can ultimately clog your pores and result in pimples.Prevent them: Rev up your treatment the week before your period: If you regularly use a cleanser with an acne-fighting ingredient such as benzoyl peroxide or salicylic acid, apply a leave-on treatment with that same active ingredient, and treat your chin, jawline, neck, and the rest of your face just to be safe.

(“You can’t predict exactly where the zit will erupt,” Dr. Zeichner says.) If you get super-bad breakouts at the same time every month, you might want to see your dermatologist or primary doc for a prescription treatment like birth control pills or another kind of hormonal therapy, which can level out your hormones to prevent the surges that lead to breakouts.

Pimples on Your Nose and Forehead

The culprit: Stress. Dr. Zeichner says your fight-or-flight stress response is the most likely trigger for T-zone breakouts. When shit hits the fan, your body releases adrenaline that can increase oil production and increase the likelihood of breakouts.

Prevent them: When stress hits (or in advance when you’re heading into a stressful week at work or school), apply a leave-on acne treatment to these areas or your entire face to be safe.

Pimples Along Your Hairline

The culprit: Hair product overload. Unless you’re going for the greasy look, you probably know better than to apply heavy-duty products like pomades near your hairline. But when you apply hair products elsewhere, and then touch your hairline to tousle your roots or smooth a flyaway, you risk clogging your pores.Prevent them: Avoid applying products near your forehead, and make sure you wash your hands after you apply hair products. When you wash your face, make sure you scrub up to the roots. (Just be gentle — overdo it, and you could cause irritation and inflammation, Dr. Zeichner says.) If your breakouts become a serious problem, use a daily toner around the hairline for extra help.

Pimples on Your Cheeks

The culprit: Your dirty phone or dirty hands. Anything that touches your face for a long period of time (i.e., about the time it takes to catch up with your mom) can transfer pore-clogging dirt or bacteria to your skin, Dr. Zeichner says.Prevent them: Clean your phone with antibacterial wipes daily, and use a hands-free device when you can. And seriously: Keep. Your. Hands. Off. Your. Face!

Pimples Around Your Mouth

The culprit: Your diet. Residue from acidic foods (think lemon and vinegar-based dressings) can irritate your skin and cause inflammation, while the greasy remnants of fried foods (like chips, fries, and basically every other delicious food) can physically block your pores. Either way, the result is the same: gnarly-looking zits around your lips.Prevent them: Use a facial cleansing wipe to remove invisible irritants around your mouth after you eat.

Pimples on Your Chest and Back

The culprit: The wrong sports bra or T-shirt. Cotton fabrics sop up sweat and keep it close to your skin. Because acne-causing bacteria thrives in moist places, wearing cotton clothes to the gym can turn your skin into a breeding ground for pimples, Dr. Zeichner says.Prevent them: Wear moisture-wicking fabrics (like a polyester-spandex blend and microfiber) when you work out. Because they whisk sweat away from the skin, you’ll be less likely to break out (especially if you lounge in your gym clothes all day.)